The pressure gauge is an item stolen by poltergeists and hidden somewhere in Draynor Manor. It is part of Professor Oddenstein's pouletmorph machine, and must be retrieved along with the rubber tube and oil can to restore Ernest during Ernest the Chicken.
This item is found submerged in the waters of the piranha-infested fountain in the south-western area of Draynor Manor. To get this item, the player must kill the piranha using poisoned fish food made from the poison (found in the witch's larder on the ground floor[UK]1st floor[US]) and the fish food (found on the 1st floor[UK]2nd floor[US] among the ghost). If you don't use poisoned fish food, the piranhas bite your fingers and cause 10 points of damage.
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